<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./react/react17.development.js"></script>
    <script src="./react/react-dom17.development.js"></script>
    <script src="./react/babel.min.js"></script>
</head>

<body>
    <div id="main"></div>
    <script type="text/babel">
        class Com extends React.Component {
            render() {
                return (<div>
                    <div style >333</div>
                </div>)
            }
        }

        ReactDOM.render(<Com />, document.getElementById("main"))
    </script>
</body>

</html>